The invention relates to a colour display tube comprising an electron gun, a getter, a display screen and a colour selection structure which is arranged in front of said display screen and which has a surface facing away from the display screen. In operation, electrons emitted by the electron gun and impinging on the colour selection structure heat said colour selection structure. This heating of the colour selection structure causes deformations of the colour selection structure, so-called "doming", which adversely affects picture quality. The side of the colour selection structure facing away from the display screen may have been treated such that it has favourable properties as regards doming.
The colour display tube further comprises a getter. The getter material is vaporised from the getter in a gettering process and is deposited on surfaces of the colour display tube. The layer of getter material thus formed improves the vacuum in the colour display tube.
It has been found that said layer of getter material influences doming. An increase of doming caused by the layer of getter material can be precluded by taking steps which prevent deposition of getter material on the colour selection structure, for example, by vaporising the getter material in a direction away from the colour selection structure. However, this imposes restrictions on the location and/or shape of the getter, and a part of the surface inside the colour display tube is not covered by getter material, which adversely affects the vacuum inside the tube.